1. Field of the Invention
This invention relates in general to a follow-up system for moving bodies and more particularly to a novel system capable of taking defensive measures against emergencies by utilizing radio signal communication.
2. Prior Art
Among conventionally used instruments or devices to provide against emergencies or threats a device may include a portable alarm or a crime prevention buzzer which are carried at all times by a person to be protected and is adapted to sound a warning by a buzzer should an emergency arise. The warning buzzer sound would be audible by the neighborhood who will then immediately inform the police or other suitable authorities or companies for prompt investigation and rescue. However, no reaction could be expected in a thinly built-up area or at midnight. An assailant who hears the buzzer sound very closely might counterattack a victim in excitement.
Abduction or kidnaps are on the remarkable increase almost all over the world. In usual cases occurence of abduction is first known to the third party when a hostage's family, for example, receives a ransom call from the abductor. The hostage's family then informs the police or the investigating authorities to request a search. The police may trace a telephone call from the abductor to follow a lead on the case. The hostage's family, however, often tends to keep the case a secret to get the hostage back safe, in which case the police is kept out of the case and can not institute the search. No prompt investigation and rescue is established.